There is always a way to do anything, you just have to be willing to pay for it. They decided this wasn't a failure mode to prepare for (read: spend money against) so they now deal with the consequences.
The cost would be so high tickets could double if it was even possible.
There are weather delays all the time. There are ATC problems all the time. But having either one of those turn into this kind of a mess is unprecedented, so there has to be something else in play here, and that "something else" is almost certainly SW screwing something up.
It really isn't. Just earlier this year:
https://www.nytimes.com/2021/08/03/business/spirit-american-...
"Spirit Airlines and American Airlines canceled hundreds of flights on Tuesday after several days of disruptions, frustrating passengers across the country."
"By midafternoon, Spirit had scrapped more than half its scheduled flights for the day, according to FlightAware, an aviation data firm. The airline canceled more than 40 percent of its flights on Monday and 19 percent on Sunday. Spirit attributed those disruptions to “a series of weather and operational challenges.”"
"American had canceled about 300 flights by the middle of the afternoon on Tuesday, about a tenth of Tuesday’s scheduled trips. The airline canceled about 18 percent of its flights on Monday and 9 percent the day before. American pinned the blame on a weekend storm that hit Dallas Fort Worth International Airport, its large hub airport."
The article indicates "upwards of 50% of our aircraft lines flow through Florida".
There's more to Florida than just Miami, and the FAA backs up the weather claim.
Meanwhile, none of the other airlines who also instituted mandates saw delays.
"This appears not to be an aviation problem so much as a Southwest problem; other airlines were able to carry on with minimal cancellations after Friday’s disruptions."
"Southwest has generally struggled with coordinating its operations as of late; it had the highest percentage of cancellations and worst on-time performance among the country’s four major airlines in June and July. The Southwest pilots union further blamed the company’s technical systems and processes for reassigning pilots when disruptions occur, claiming that these are long-standing problems that executives have failed to fix for years. The airline has struggled with rerouting pilots partly because it uses a “point-to-point” system, which focuses on flying passengers directly to their destinations. This is opposed to the “hub-and-spoke” model that American Airlines uses, in which passengers are often first routed to a main base of operations before departing for their final destination. While the point-to-point system has the advantage of reducing travel times and the number of connecting flights, it can be difficult to adapt to unexpected situations. Southwest’s point-to-point network also covers an unusually large geographic area, which makes reassigning pilots even more complicated."
Or do they top-up at B in order to reach C?
Sometimes the backup plan is occasional failure. Resiliency is expensive. We don't tend to own up to our decisions when we (companies, individuals, etc.) opt to pay for for limited resilience. But besides our irrational denials, it's often a rational trade off.
Take the recent FB downtime for example. FB's bigness means that FB downtime had some significance but FB is not critical infrastructure. Thousands of decisions, trade offs and compromises reflect that. If there's trade off between costs or speed of software development and resilience... FB will/should not always choose resilience. That's rational.
Being stranded for a day because airlines is something that happens n% of the time. Cost of the mode.